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Adsorption Mechanism Of Macroporous Resin

Jul 20, 2020

Before talking about macroporous adsorption resin, let us first understand what is macroporous adsorption resin. Macroporous adsorption resin is a kind of macroporous adsorption resin without exchange group and macroporous structure. It has a good macroporous network structure and With a large specific surface area, organic matter in aqueous solution can be selectively adsorbed physically. It is a new organic polymer adsorbent developed in the 1960s and has been widely used in environmental protection, food, medicine and other fields.

The adsorption effect of macroporous resin is to rely on the van der Waals attraction between it and the adsorbed molecules (adsorbents), and work through physical adsorption through its huge specific surface, so that organic compounds can pass through a certain solvent according to the adsorption force and molecular weight. Separate elution to achieve different purposes such as separation, purification, impurity removal, and concentration. Macroporous adsorption resin is a separation material that combines the principles of adsorption and screening. The adsorption of macroporous resin is essentially a phenomenon of surface adsorption caused by highly dispersed objects or uneven forces on surface molecules. This adsorption performance is due to van der Waals attraction or the formation of hydrogen bonds; at the same time, due to the phenomenon of macroporous resin The porous structure allows it to screen substances with different molecular sizes. Through the above-mentioned adsorption and screening principle, the organic compounds are separated by a certain solvent on the macroporous adsorption resin according to the different adsorption capacity and the size of the molecular weight.

   The choice of adsorption and desorption conditions directly affects the quality of the macroporous adsorption resin adsorption process. Therefore, various factors should be comprehensively considered during the entire process to determine the best adsorption and desorption conditions. There are many factors that affect resin adsorption, mainly the properties of the separated components (polarity and molecular size, etc.), the properties of the sample solvent (solubility of the solvent to the components, salt concentration and pH value), the concentration of the sample solution and the flow rate of the adsorption water Wait.

Generally, molecules with larger polarity are suitable for separation on medium-polar resins, and molecules with small polarity are suitable for separation on non-polar resins; larger pore size resins are used for larger compounds; appropriate amount of inorganic salt can be added to the sample solution to increase resin adsorption Quantity; acidic compounds are easily adsorbed in acidic liquids, basic compounds are easily adsorbed in alkaline liquids, and neutral compounds are adsorbed in neutral liquids; generally, the lower the concentration of the sample liquid, the better the adsorption; for the choice of drip rate, It is better to ensure that the resin can fully contact and absorb the sample liquid. The factors affecting the desorption conditions include the type, concentration, pH value, flow rate and so on of the eluent. The eluent can be methanol, ethanol, acetone, ethyl acetate, etc., and different eluents and different eluent concentrations should be selected according to the strength of the adsorption of different substances on the resin; by changing the elution The pH value of the reagent can change the molecular morphology of the adsorbate and is easy to elute; the elution flow rate is generally controlled at 0.5 ~ 5mL/min.